Rutherford's alpha ray scattering experiment Why didn't the alpha particles collect electrons on their way while penetrating the gold foil in Rutherford's experiment?
 A: The experiment at the time was checking the atomic model of positive and negative changes making up the atom, the "plumb pudding" model at the time
Rutherford's observations:
Rutherford made 3 observations:
.    Most of the fast, highly charged alpha particles went whizzing straight through undeflected. This was the expected result for all of the particles if the plum pudding model was correct.
.    Some of the alpha particles were deflected back through large angles. This was not expected.
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A very small number of alpha particles were deflected backwards! This was definitely not as expected. Rutherford later remarked "It was as incredible as if you fired a 15-inch shell at a piece of tissue paper and it came back at you!"
The "plumb pudding" model was out, the atom as we know it with a nucleus and electrons in orbitals around it was born.
Now if you are asking why the alpha ion going through the shells of electrons does not become neutralized , it is because  for an electron to fall into the empty energy level the energy must be exact within a width, The energy from the nuclear decay is of order of MeV. The energy of the atomic levels is of order of eV. There is very small probability of interaction with an electron in an orbital, before the alpha particle interacts with the nucleus or goes through the foil not interacting.
